Defying U.S., Colombia Halts Aerial Spraying of Crops Used to Make Cocaine

BOGOTÁ, Colombia — The government of Colombia on Thursday night rejected a major tool in the American-backed antidrug campaign — ordering a halt to the aerial spraying of the country’s vast illegal plantings of coca, the crop used to make cocaine, citing concerns that the spray causes cancer.

The decision ends a program that has continued for more than two decades, raising questions about the viability of long-accepted strategies in the war on drugs in the region.

Colombia is one of the closest allies of the United States in Latin America and its most stalwart partner on antidrug policy, but the change of strategy has the potential to add a new element of tension to the relationship.

Just last week, American officials warned that the amount of land used to grow coca in Colombia grew by 39 percent last year as aerial spraying to kill or stunt the crop, already a contentious issue here, declined.

“The folks who run counternarcotics never want to give up any of their tools, and there are pockets of discontent inside the U.S. government with this decision,” said Adam Isacson, a senior associate of the Washington Office on Latin America, a research group.

“Colombia and the United States have been in lock step on a hard-line approach” in how to fight drug trafficking, he added. “It’s the first time there’s been light between the two countries on what the strategy should be, in recent memory.”

The decision to halt the spraying, which was backed by President Juan Manuel Santos, came after an agency of the World Health Organization declared in March that the herbicide used here, a chemical called glyphosate, probably causes cancer in humans.

The chemical, the active ingredient in the popular weedkiller Roundup, is the most widely used herbicide in the world. Colombian officials have said that a previous Supreme Court ruling in their country called for an end to the spraying if health concerns involving the chemical were found.

The United States Environmental Protection Agency has determined that there is a “lack of convincing evidence” to consider it a cancer risk to humans.

Before Thursday’s decision, the United States had pressed the Colombian government to continue the spraying program. The American ambassador in Bogotá, Kevin Whitaker, published an op-ed article in El Tiempo, one of the country’s main newspapers, over the weekend, defending the program.

But he has also stressed that Colombia’s decision would not harm diplomatic relations.

“This is their sovereign decision to make, and we will respect that and we will continue to use the tools that are available to us, as Colombia wishes us to do, to continue to be a partner with them in this fight,” Mr. Whitaker said in an interview a day before the decision was taken.

“We have lots of tools to help Colombia address the problem of transnational crime and narco-trafficking.”

He said that includes providing intelligence on drug traffickers, encouraging farmers to grow other crops, intercepting drug shipments, focusing on shutting down drug labs and supporting efforts to pull up and destroy coca plants by hand.

Thursday’s decision involved only the use of the herbicide in the coca spraying program. The government has not moved to ban use of the herbicide by farmers who grow legal crops and use it to kill weeds.

The spraying program was steeped in controversy even before the declaration was made in March by the International Agency for Research on Cancer.

Colombia is the only coca-producing country that uses airplanes to spray and kill the crop. The other major producers, Peru and Bolivia, have shunned spraying.

Critics of spraying in Colombia said that it was harmful to the health of rural residents and that it caused environmental damage.

The spraying also alienated the poor farmers who have often felt that they had little choice but to grow coca to feed their families.

But opponents of the spraying ban have argued that ending spraying could lead to a boom in cocaine production and favor traffickers and rebel groups like the Revolutionary Armed Forces of Colombia, or FARC, which depends on the drug trade for much of its financing and has advocated an end to spraying.

They have also pointed out that one alternative, eradicating plants by hand, is dangerous because it involves sending troops and workers into areas controlled by traffickers and guerrilla troops. Many eradication workers have been killed and wounded by land mines or in armed confrontations in drug-growing areas.

Spraying with glyphosate began in the 1990s on a small scale and by the early 2000s it was established as a crucial aspect of Plan Colombia, a multibillion dollar push by the United States to aid in fighting rebel groups and drug traffickers in the country.

It reached its peak in 2006, when more than 405,000 acres were sprayed, according to data compiled for the White House Office of National Drug Control Policy.

But aerial spraying has fallen sharply over the last two years, even as coca plantings jumped. Last year, 137,000 acres were sprayed, while the amount of land planted with coca increased to 276,758 acres in Colombia, compared with 198,919 acres the previous year.

Daniel Mejía, the director of the Center for Security and Drug Studies, a research group in Bogotá, said that spraying was inefficient and counterproductive.

“I would recommend attacking the links in the chain of drug trafficking, the labs where cocaine is processed, the large shipments of chemicals, which is really where the hard drug trafficking is, where organized crime is,” Mr. Mejía said. “It has been shown that attacking the farmers doesn’t work.”

Rafael Nieto, a former vice-minister of justice, questioned the rationale behind halting spraying, saying that more eradication workers would be put at risk.

“If the spraying is stopped, the income of the drug traffickers, the criminal gangs and the guerrillas will go up substantially and so will the number of dead and wounded,” Mr. Nieto said. “Coca and cocaine production would also go up, and there would be more addicts and more people will die.”

The impact of the decision on the peace talks underway between the government and the FARC are uncertain. Some critics of the decision say that it removes a critical element of pressure on the group that could help push it toward a deal to lay down its arms.

The two sides have reached a preliminary deal on cooperating to fight drug trafficking, which would go into effect if an overall peace deal is reached. It calls for the government to work with rural communities to help them grow legal crops and increase government services in those areas. It says that spraying could be used only as a last resort.

On Monday, the government said that the armed forces had raided 63 illegal mines operated by the FARC to extract gold and other minerals. It said shutting down the mines would take away millions of dollars in monthly income for the group.

Susan Abad contributed reporting.

A version of this article appears in print on , on Page A1 of the New York edition with the headline: Defying U.S., Colombia Ends a Drug Tactic. Order Reprints | Today’s Paper | Subscribe